Power operated rotary knives have been used in commercial meat processing operations to trim fat and connective tissue from meat, trim pieces of meat from bones, and to produce meat slices. Such knives usually comprise a handle, blade housing and a rotary knife blade. The knife blade includes an annular body and driving gear teeth projecting axially from the body oppositely from the blade cutting section. The blade housing supports and maintains the position of the blade relative to the knife as the blade is rotated. A pinion gear mounted in a head member of the handle engages the driving gear teeth to rotate the knife blade. The pinion gear, in turn, is driven by a long, flexible drive shaft that extends through the handle. The knife operator wields the knife relatively freely at a meat cutting work station that is remote from the driving motor.
The blade of a power operated rotary knife must be replaced periodically. To permit easy removal of the blade from the blade housing, a split blade housing has been employed. Such a split blade housing is disclosed in U.S. Pat. No. 6,662,452, assigned to the assignee of the present invention. The '452 patent is incorporated herein in its entirety by reference.
In prior art rotary knives, the opening or split of the blade housing was located in a recessed portion of the blade housing that was radially and axially aligned with the pinion gear. The recessed portion of the blade housing provided a clearance region the drive teeth of the pinion gear which extended outwardly from the head member to engage the gear teeth of the knife blade. The split in the blade housing was aligned with the pinion gear recessed portion of the housing because the height of the blade housing in an axial direction is a minimum at that position.
It has been found that depending upon consistency the material being cut or trimmed with the power operated rotary knife, the opening or split of the blade housing tended to provide a passageway for the pieces of fat, meat and bone and other debris materials collected on the cutting section of the knife blade during use to migrate to the pinion gear and the intersection of the pinion gear and the drive teeth of the knife blade. Collecting debris materials in the region of the meshing of the pinion gear and knife blade drive teeth is undesirable because the heat generated by the driving engagement tends to “cook” the debris creating a sticky build up on the pinion gear and drive teeth and generating even more heat. Moreover, such a build up of debris and sticky materials may lead to increased vibration of the knife during operation and shortened blade and pinion gear life, all of which are detrimental to rotary knife performance.
What is needed is split blade housing for a power operated rotary knife that reduces the propensity of debris materials from being routed from the blade section of the knife blade to the a region of the pinion gear and knife blade drive teeth.